[PATCH] powerpc/64s: Fix VAS mm use after free

[Sachin Sant]

> On 07-Jun-2023, at 3:40 PM, Nicholas Piggin <npiggin at gmail.com> wrote:
> 
> The refcount on mm is dropped before the coprocessor is detached.
> 
> Reported-by: Sachin Sant <sachinp at linux.ibm.com>
> Fixes: 7bc6f71bdff5f ("powerpc/vas: Define and use common vas_window struct")
> Fixes: b22f2d88e435c ("powerpc/pseries/vas: Integrate API with open/close windows")
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
> How's this for fixing your vas_deallocate_window warning at
> radix_tlb.c:991 ?
> 
> I added a few new warnings in the TLB flush code recently which is
> why these new warns are showing up.
> 

Thanks Nick. This fixes the reported warning.
Nx-gzip as well as mce error inject tests completed successfully.

Tested-by: Sachin Sant <sachinp at linux.ibm.com>

- Sachin